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Screwdriver antenna's - recommendations?

Discussion in 'Mobile Radio Systems' started by WB9SFK, Jan 21, 2011.

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  1. WB9SFK

    WB9SFK Ham Member QRZ Page

    Until recently I had not paid any attention to screwdriver antenna's. Now I've seen a lot of them on vehicles. Research has provided me with numerous brands being available (Of course everyone sell's the best). I'm not concerned about the price, but rather the quality, the gain and loss specifications. Your opinions on what to buy, and why, would be appreciated.

    Thanks!

    Barry
     
  2. KD0CAC

    KD0CAC Ham Member QRZ Page

  3. VE6NS

    VE6NS Platinum Subscriber Platinum Subscriber QRZ Page

    I'm running a Tarheel 300A on my Jeep and a Little Tarheel II on the wifes Jeep.
    Love then both, and customer service is second to none!

    Tarheel
     
  4. WB2WIK

    WB2WIK Platinum Subscriber Platinum Subscriber QRZ Page

    I have a Hi-Q 5-80 and it's pretty wonderful.

    However there are a couple that are evidently as good or better, which I haven't used.

    Alan K0BG is a real HF mobile hound and usually has good advice on this stuff, I'd see what he's written up lately: http://www.k0bg.com
     
  5. WB2WIK

    WB2WIK Platinum Subscriber Platinum Subscriber QRZ Page

    BTW I meant to mention and didn't (senior moment) that the installation, placement and grounding of any HF mobile antenna can be more important than the antenna itself.

    K0BG also has a lot of good advice on that.
     
  6. KH6AQ

    KH6AQ Ham Member QRZ Page

    I have a Tarheel 200A HP and a Yaesu ATAS-120A. Both work well. The ATAS-120A is great on 30-6 meters and doesn't require a large mount. On 40 meters it can work well if mounted right. Mine has a radiation efficiency of 10% on 40 meters - this is high - because it's mounted on the roof.

    An HF mobile antenna and vehicle form a vertical dipole. The vehicle does radiate. The screwdriver is only half of the vertical dipole. Mounted on or close to the roof you have the vehicle and the screwdriver working together. Mounted on or close to the bumper you have the vehicle and the screwdriving opposing one another.

    So, a small screwdriver mounted high on the vehicle can out perform a large screwdriver mounted low on the vehicle.
     
  7. WB2WIK

    WB2WIK Platinum Subscriber Platinum Subscriber QRZ Page

    Yep, I agree and have found this empirically over the years.

    In '88-89-90 at the peak of Cycle 22, I had a 96" SS whip (cut down CB whip) on my station wagon, in a Motorola ball mount up high on the rear fender, actually close to the roof line. Yes, it hit tree limbs a lot.

    But running only 10 meters with a Radio Shack HTX-100 (25W) and that antenna, I had DXCC in one weekend during the ARRL 10m contest in December '89. I also broke some amazing pileups with it, if I was parked at an advantageous location like the beach or on a hilltop.

    Broke a pileup into an OD3 in Lebanon on 10m using 25W and that whip, while on the 405 freeway in Los Angeles, at a great spot where it crosses Mulholland (about 1300' elevation). To complete the QSO I pulled over before going back down the hill.:p
     
  8. N5YPJ

    N5YPJ QRZ Moderator QRZ Page

    Check out Alan K0BG's web site. If it relates to mobile he knows it and has probably done it at least onnce.
     
  9. M0GVZ

    M0GVZ Ham Member QRZ Page

    Seconded. I run a Little Tarheel II with a 6ft whip mounted in the center of the roof of my Ford Mondeo. With just 50W on 20m band I can work East Coast USA from East Coast England.

    If you go for a screwdriver with a short whip such as ATAS120 or Little Tarheel, if you're prepared to lose the higher bands, the performace increase from fitting a longer whip is well worth it. For my Litte Tarheel, changing to the 6ft whip gave me a 6dB or 2 S-point improvement on both TX and RX. It was pretty much point for point with a Diamond CP6 I was using on 20m up and was better than the CP6 on 40m.
     
  10. KB0YYO

    KB0YYO Premium Subscriber QRZ Page

    Conor
    Thanks for the tip on the 6 ft whip. I have a Lil Tar Heel ll but not mounted yet. I will certainly look into this 6 ft "helper".
    I will be mounting the Tar Heel ll on a Semi ( lorry) come spring.
     
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